Top Banner
CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGN Manoj Khanna Principal Scientist & In Charge Farm Operation Service Unit (FOSU) Water Technology Centre ICAR-Indian Agricultural Research Institute New Delhi
31

CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Nov 03, 2018

Download

Documents

hanguyet
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER

REQUIREMENTS FOR

MICROIRRIGATION SYSTEM

DESIGNManoj Khanna

Principal Scientist &

In Charge Farm Operation Service Unit (FOSU)

Water Technology Centre

ICAR-Indian Agricultural Research Institute

New Delhi

Page 2: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Crop Water Requirement

Crop water requirement (WR) is the quantity

of water utilized by a crop, irrespective of its

source for obtaining maximum yield in a

particular area without any/minimum

adverse effect on soil properties.

CWR = Etc/CU + Unavoidable application losses + Special operation needs

CWR = Irrigation + Effective rainfall + Gr water contribution + Change in

soil water storage

Page 3: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Crop Evapotranspiration (Etc)

Etc = Eto x Kc

Eto: Reference Evapotranspiration is estimated based on

climatic data of the place

It is estimated using Modified Penman Monteith Method

(Details can be seen in FAO Irrigation and Drainage Paper 56)

Kc: Crop factor (based on crop growth stage)

Page 4: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Input Data Required

Monthly/Daily Climatic data

Minimum/Maximum Temperature

Relative Humidity

Sunshine duration

Wind Speed

Radiation

Rainfall (Effective Rainfall)

Crop data

Crop duration (sowing/harvesting date)

Crop factor

Root zone depth

Soil Data

Soil Type

Water holding capacity (Field Capacity/wilting Point)

Page 5: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Effective Rainfall Based on

Fixed Percentage

Dependedable rain formula given by FAO

Empirical formulas

USDA Soil Conservation Service Formula

Not included in Irrigation requirement

Page 6: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Irrigation Scheduling

Based on

Fixed depletion percentage

Irrigate at fixed interval (Frequent irrigation

in microirrigation)

Irrigate at critical stages

Page 7: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Irrigation Efficiency

Surface Irrigation: 50%

Sprinkler Irrigation: 80%

Drip Irrigation: 90%

Page 8: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Irrigation Schedules/Planning

Develop indicative irrigation schedules to improve water

management

Evaluate the current irrigation practices and their

associated crop water productivity;

Evaluate crop production under rainfed conditions and

assess feasibility of supplementary irrigation;

Develop alternative water delivery schedules under

restricted water supply conditions.

Page 9: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Irrigation Schedules/Planning

Rainfall

Water stress coefficient (Ks)

Crop Etc

Root zone depletion

Net irrigation

Deficit: amount of water (in mm) below field

capacity

Irrigation losses

Gross irrigation

Flow

Soil Water Balance

Page 10: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

CROP WATER REQUIREMENT ESTIMATION

USING CROPWAT

Demonstration of FAO CROPWAT 8.0 for

windows with example

Demonstration of FAO CLIMWAT 2.0

Page 11: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Irrigation Methods

(Pressurized) Drip

Sprinkler

Micro sprinkler

Characteristics

Low flow requires good filtration

Reduced application losses

Reduced runoff

Controlled application

Page 12: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Typical Layout of Drip Irrigation-Fertigation System

Page 13: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING
Page 14: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING
Page 15: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING
Page 16: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Drip irrigation in potato

Crop Increase

in yield,

%

Water

saving,

%

Tomato 25-50 40-60

Onion 25-40 20-30

Potato 20-30 40-50

Cabbage 30-40 50-60

Cauliflower 60-80 30-40

Drip irrigation in Tomato Drip irrigation in Onion Drip irrigation in Cabbage

Drip irrigation in Cauliflower

INCREASE IN YIELD AND WATER SAVING THROUGH DRIP

IRRIGATION IN COMPARISON TO CONVENTIONAL

SURFACE IRRIGATION METHODS IN VEGETABLE CROPS

Page 17: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING
Page 18: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING
Page 19: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Components of Drip Irrigation

System

Main line HDPE/ PVC

Sub main line HDPE/ PVC

Laterals LLDPE/ LDPE

Emitters Line source/ Point Source/ Disk Source

Control system Filters/ Controllers

Fertigation system Tanks/ Venturi System

Page 20: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Advantages of Drip Irrigation

System

Better Soil water regime for higher crop yield

Water and Fertilizer savings

Less labour intensive

Land levelling not required

Minimal weed problem

Automatic control is possible

Less incidence of pest and diseases

Page 21: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Adaptability and Limitations of Drip

Irrigation System

All Types of fruits, vegetables, vines, cotton,

sugarcane

Arid and semi-arid areas

Hilly areas, Coastal, Waste lands

Operational problems such as clogging

High initial cost

Higher Skill s required for operation

Adaptability

Limitations

Page 22: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Pump set

Main Line

Sub Main

Line

Emitter

Lateral Line

Layout of drip irrigation system

Page 23: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Design of Drip Irrigation Systems

Design Steps

Crop Water Requirement (Monthly, Litres)

NAKKE V pcp

V = Volume of water required (litres)

Ep = Mean pan evaporation for the month (mm/day)

Kc = Crop factor

Kp = Pan factor

A = Area to be irrigated (Sq.m.)

N = Number of days in a month

Page 24: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Design of Drip Irrigation Systems

Design Steps

Crop Water Requirement (Monthly, Litres)

ARVV en Net Volume of water

to be applied=

Where, Re = Effective rainfall (mm)

Page 25: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Design of Drip Irrigation Systems

Design Steps Crop Water Requirement (Monthly, Litres)

Number of operating hours

of System during a month (T)=

Where, Wp = percentage wetting

edischdripperPlantsofNoplantperdrippersofNo

WVT

pn

arg..

Page 26: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Design of Drip Irrigation Systems

Design Steps

Crop Water Requirement (Monthly, Litres)

Number of operating hours of

System per application (Tm)=

Where, Nm = Number of application per month

mN

T

Page 27: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Hydraulic Design of Drip Irrigation

Systems

The flow through nth section of pipe given

by

Where:

qi = discharge from each emitter LPH;

Qn= flow passing through nth section LPH;

m= total number of emitters in lateral line;

i= emitter number in lateral line

m

ni

in qQ

m

ni

in qQ

Page 28: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Hydraulic Design of Drip Irrigation

Systems

The characteristics of flow (laminar or turbulent)

are identified by Reynolds’s number which is

given by

Where:Vn = Mean velocity of flow through the nth section of

pipe, m/sec;

D = inner diameter of pipe, m;

= kinematic viscosity of water in m2/sec

Laminar flow Ren<2000

Turbulent flow Ren> 2000

m

ni

in qQ

DVn

n Re

Page 29: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Hydraulic Design of Drip Irrigation

Systems

Head loss for pipe flow in both laminar and

turbulent range is given by

Where:

Fn = head loss due to friction in nth section of line

fn = friction factor in nth section of line

L = length of nth section of line

G = acceleration due to gravity

Laminar flow Turbulent flow

m

ni

in qQ

gD

VLfF

nn

n2

2

n

nfRe

64

25.0Re

316.0

n

nf

Page 30: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING

Hydraulic Design of Drip Irrigation

Systems

Cumulative friction head loss F for pipe flow in

lateral or main line is given by

m

ni

in qQ

n

n

nFF1

Page 31: CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM DESIGNcwc.gov.in/main/Download_Index/Crop Water Requirements for... · CROP WATER REQUIREMENTS FOR MICROIRRIGATION SYSTEM ... USING